A Caltech Library Service

Marine20—The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP)

Heaton, Timothy J. and Köhler, Peter and Butzin, Martin and Bard, Edouard and Reimer, Ron W. and Austin, William E. N. and Bronk Ramsey, Christopher and Grootes, Pieter M. and Hughen, Konrad A. and Kromer, Bernd and Reimer, Paula J. and Adkins, Jess and Burke, Andrea and Cook, Mea S. and Olsen, Jesper and Skinner, Luke C. (2020) Marine20—The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP). Radiocarbon, 62 (4). pp. 779-820. ISSN 0033-8222.

[img] PDF - Published Version
Creative Commons Attribution.


Use this Persistent URL to link to this item:


The concentration of radiocarbon (¹⁴C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their ¹⁴C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 ¹⁴C curve and reconstructed changes in CO₂ obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric ¹⁴C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric ¹⁴C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base

Item Type:Article
Related URLs:
URLURL TypeDescription ItemData
Heaton, Timothy J.0000-0002-9994-142X
Köhler, Peter0000-0003-0904-8484
Butzin, Martin0000-0002-9275-7304
Bard, Edouard0000-0002-7237-8622
Reimer, Ron W.0000-0001-7939-6623
Austin, William E. N.0000-0001-6544-3468
Bronk Ramsey, Christopher0000-0002-8641-9309
Grootes, Pieter M.0000-0003-4265-3168
Hughen, Konrad A.0000-0003-3201-934X
Kromer, Bernd0000-0003-1058-4436
Reimer, Paula J.0000-0001-9238-2146
Adkins, Jess0000-0002-3174-5190
Burke, Andrea0000-0002-3754-1498
Cook, Mea S.0000-0003-3786-6353
Olsen, Jesper0000-0002-4445-5520
Skinner, Luke C.0000-0002-5050-0244
Additional Information:© 2020 by the Arizona Board of Regents on behalf of the University of Arizona. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Published online by Cambridge University Press: 12 August 2020. We would like to thank Jeremy Oakley and Richard Bintanja for informative discussions during the development of this work. T.J. Heaton is supported by a Leverhulme Trust Fellowship RF-2019-140\9, “Improving the Measurement of Time Using Radiocarbon”. M Butzin is supported by the German Federal Ministry of Education and Research (BMBF), as Research for Sustainability initiative (FONA); through the PalMod project (grant numbers: 01LP1505B, 01LP1919A). E. Bard is supported by EQUIPEX ASTER-CEREGE and ANR CARBOTRYDH. Meetings of the IntCal Marine Focus group have been supported by Collège de France. Data are available on the PANGAEA database at doi:10.1594/PANGAEA.914500. Author Contributions: TJH led this study and performed the Bayesian modeling. The general setup of Marine20 has been designed through discussions of the IntCal Marine Focus group led by EB. PK provided simulation results using the BICYCLE model, MB simulation results from the LSG OGCM. The manuscript has been written by TJH with large contributions from PK. RWR performed initial modeling tests incorporating pCO₂ data and recalculated ΔR values in the marine reservoir correction database with Marine20. All other co-authors provided expert knowledge and contributions to both discussions and the writing of the manuscript.
Funding AgencyGrant Number
Leverhulme TrustRF-2019-140\9
Bundesministerium für Bildung und Forschung (BMBF)01LP1505B
Bundesministerium für Bildung und Forschung (BMBF)01LP1919A
Agence Nationale pour la Recherche (ANR)UNSPECIFIED
Subject Keywords:Bayesian modeling; calibration; carbon cycle; computer model; marine environment
Issue or Number:4
Record Number:CaltechAUTHORS:20201209-105155334
Persistent URL:
Official Citation:Heaton, T., Köhler, P., Butzin, M., Bard, E., Reimer, R., Austin, W., . . . Skinner, L. (2020). Marine20—The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP). Radiocarbon, 62(4), 779-820. doi:10.1017/RDC.2020.68
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106974
Deposited By: Tony Diaz
Deposited On:09 Dec 2020 19:23
Last Modified:09 Dec 2020 19:23

Repository Staff Only: item control page